The Doctor, Amy, and Rory are awe-struck by their first sight of Hope Eternal, a super-earth bigger than Earth itself with heavy gravity, volcanoes, and a crust loaded with mineral deposits. But their wonder is cut short when they discover a body dumped on the ground. Yet the corpse is not alien: he's human, albeit unlike any human Amy and Rory have ever seen. The Nu-Humans have adapted their genes to fit their new environment, but now they are facing a terrible threat. Can the Doctor find out who is killing Nu-Humans before he, Amy, and Rory are tried for murder?